Carriage control at tabulation rebounding



Aug. 4, 1953 H. c. YAEGER CARRIAGE CONTROL AT TABULATION REBOUNDING Filed Dec. 12, 1950 Aug. 4, 1953 H. c. YAEGER 2,647,611

CARRIAGE CONTROL AT TABULATION REBOUNDING Fi led Dec. 12, 1950 2 Sheets-Sheet 2 illlll HARRY C K4565? WWW ATTORNEY Patented Aug. 4, 1953 UNITED STATES PATENT OFFICE CARRIAGE CONTROL AT TABULATION REBOUNDING Harry 0. Yaeger, West Hartford, Conn., assignor to Underwood Corporation, New York, N. Y., a

corporation of Delaware Application December 12, 1950, Serial No. 200,470

that the carriage will settle in the intended letter H feed position.

Devices of this general nature are old and known in the art, but are either complicated or are apt to function unreliably, particularly if the letter feed pitch of the carriage is small. Furthermore, a great many machines sold are equipped with decimal tabulating mechanism, which further complicates the problem of providing simple and reliably effective control to assure settling of the carriage in the required letter feed position.

It is an object of the invention to provide for reliable carriage control at the end of each tabulation through efiicient, simple and reliably exercised control over the escapement wheel.

It is another object of the invention to provide a rebound controlling device which is capable of controlling reliably and efficiently a letter feed carriage at the conclusions of tabulations even though the machine has a small letter feed pitch. v

A still further object is to provide a reverse-rotation checking means for the escapement wheel and to control efliciently and reliably such means for activation during tabulations and for deactivation a definite time interval after escapement control is reestablished at the end of the tabulating runs, the escapement and the reverse-rotation checking means cooperating to assure that the carriage settles always in the intended letter feed position.

A still further object is to provide in association with the escapement teeth of the escapement wheel'a reliablyoperative reverse-rotation checking means, which is cooperatively controlled in conjunction with the escapement to insure settling of the carriage in the proper letter feed position.

Other objects and advantages will be evident from the detailed description which follows.

Referring now to the drawings:

Figure 1 is a right hand sectional side elevation of a typewriter carriage and supporting structure, together with a letter feed escapement for the carriage and a power tabulating mechanism,

Figure 2 is a perspective View looking from the right rearward portion of the machine upwardly at an angle onto the letter feed escapement mechanism and associated rebound control mechanism, all parts being shown in their normally prevailing positions,

Figure 3 is a bottom elevation of the escapement mechanism, the rear portion of such mechanism facing toward the top of the sheet, and the escapement having been conditioned for tabulating travel of the carriage and the rebound checking device having been capacitated,

' Figure 4 is abottom view similar to Figure 3,

but the parts are illustrated in positions which they assume at the instant of carriage rebounding, and finally,

Figure 5 is a bottom elevation similar to Figures 3 and 4, with the parts shown in their normal, restored positions, identical as in the perspective illustration of Figure 2.

Directing attention now particularly to Figure 1, a carriage I I is adapted to travel in letter feed and return directions upon a trackway I2 which constitutes part of the framework of the machine, the carriage having a rail l3 which by means of anti-friction elements M is guided upon the trackway I2. Above the rail E3, the carriage ll supports a usual platen roll i5 and at the rear a rack bar [6 has a series of usual key-settable tabulating stops ll arranged at letter space intervals. A spring motor 58 supported on the framework of the machine by means of a strap connection urges the carriage I I constantly leftwardly, that is, in letter feed direction. Opposite directional movements of the carriage are translated into opposite rotational movements of an escapement wheel 20. The latter is arranged on the lower end of a vertical shaft 2! which at the top has a pinion 22 in mesh with a carriage-supported rack 23. The wheel 20, the shaft 2! and the pinion 22 comprise an assembly rotatably mounted by an upper bracket 24 and a lower bracket 25.

Normally the carriage is held at rest against the urge of the spring motor H3 in that one of the teeth 28 on the escapement wheel 20, see Figures 2 and 5, abuts against the end of a holding dog 21. The dog N is carried pivotally at 29 on the underside of an escapement rocker 30 and the latter is rockably mounted on trunnions 3 I. Said rocker carries on the top side a usual stepping dog 32 which normally is fully above the teeth of the escapement wheel 20, and held advanced in respect to the holding dog 2? by meansof a spring 33. The spring, by having an anchorage on a pin 34 of the dog 27, serves also to bias the latter to swing into the orbit of the wheel teeth 28.

Incidental to each typing operation the escapement rocker 36 is vibrated between limits in a usual manner, first to swing the dog 21 downwardly therewith clear of the active Wheel tooth to free the carriage for letter feed stepping under power of the spring motor l8. This swings the stepping dog 32 temporarily into the path of the next wheel tooth, and when the escapement rocker 30 vibrates oppositely, the holding dog 27 will intercept the wheel 20 by the next tooth 28, the stepping dog 32 meanwhile assuming again a position clear of the escapement wheel. The pin 3'4 :on'the dog H is straddled by a notch provided in the rocker 30 for establishing pivotal limits for said dog. During carriage return the escapement wheel 20 rotates in a direction opposite to the accurate intended letter feedposition. atthe end;-

of each tabulation has been devised particularly to operate also reliably in conjunction with decimal tabulators, such as the --power tabulating mechanism disclosed in the patent to Yaeger, No. 2,386,060.

The shown tabulating mechanism comprises a" normally retracted counterstop reed 3! underneaththe tabulator rack [6 which is projectable from the position seen in Figure 1, upwardly into the range of a tabulator stop: ll. At operation of a tabulator key 38, a transversely extending lever 39 in the machine receives downward motion to depress a lever 40 having a hook element 59 to descend on a lug of a power actuator i. "I'his'engages a snatch pawl 53 with a constantly turning, toothed shait member '52. Said actuator 5| at one end is borne pivotally on a pendant arm 54 and a spring 55 normally urges the same rearwardly and away from the toothed power member 52, to occupy the idlerposition seen in Figure l. The actuator receives a power movement toward the front of the machine when the snatch pawl is brought 'int engagement with the toothed shaft 52. There ensues then an operation of a link 55 which rocks a structure 51, which in turn by means of a link '58 and a lever 60 imparts an upward movement to the reed 31 against the action of a return spring 6i. The upper end of the reed 31 reaches through a perforation provided. in a top plate 63 of a tabulator housing E i and said perforation is wide enough in the direction of carriage'travel to give said reed 3'? some capacity for lateral movement to the right for a latch edge '65 on the right of the reed at projection of the latter to catch over a ledge provided by a plate" 66. This latching action takes place under the tension of a spring, indicated at 61, which pulls the reed 3'? rightwardly a fraction of a letter feed space. During'the projection ofthe reed 31 the lever S0 operates a bell crank 68 carried pivotally at "IE3 upon an ear '69 of the bracket 25. During the first part ofthe projecting movement for the reed .31 a downreaching arm H of the bell crank 68 moves first idly from the position seen in Figure 5. 'After the upper end of the reed 31 has moved abovethe lower edge of the tabulator stop 17, said arm H will pick up and swing the holding dog' 21 clear of the escapement wheel tooth which has to this moment been active. The spring motor I8 is thus enabled to pull the carriage. in letter feed. direction until a tabulator stop 1! engages and displaces the projected reed 37 leftwardly to the limit in the perforation. This places the latch edge65 free of the plate lifi so that return spring 6| associated with the reed will retract'the latter to normal position. During such retraction of the reed, the downreaching arm H of th'elever 68 swings rearwardly and renders the holding dog 2'! free for movement to e'fiective position under the power of the spring 33, see Figures 2 and 5. The movement of the arm H in regard to controllingthe dog 21 is such that'the latter will move into advancerotation blocking position with reference to the .escapementwheel teeth. 25 before the tabulator reed 37 moves fully below the tabulator stop ll. Thus, at the end of each tabulating run the dog 2? reliably assumes control over the carriage so that the latter cannot pass beyond the intended letter feed position. The sudden violent arrest of the carriage at the encounter of the tabulator stop H. with the reed 37, especially atfer long .tab'ulating runs, results in violent rebounding action of the carriage, and here the problem is to provide efiicient means to cause 'thewequird-tooth of the escapement wheel to settlesagainst the holding dog 2! so as in turn to assure settling of the carriage in the proper letter feed position. In practical machines there are of necessity various points of looseness'and opportunity for yield in the connecting structurev betweenthe escapement wheel 20 and'the carriage supported stop ll, so that the escapement wheel 2E3 at violent tabulating arrests of the carriage will get temporarily out of step withthe carriage. While the contributing factors which cause the escapement wheel 20 to get out of step with'the carriage are present at various points, their aggregative presence is schematically indicated by showing play in the toothed engagement between the pinion 22 .and the rack 23 in Figures 3 to 5, inclusive. 'The fact that the escapement wheel gets out of step with the carriage at tabulating arrest of the latter has been the source of great difficulty especially in fine letter feed pitch machines, in that rebounding controls applied to the carriage failed to reliably control theescapement wheel at the vital instant.

According to the invention reliable control of the escapernent wheel is assured at the terminations of all tabulating runs, by provision of a device which during rebounding of the carriage controls the escapement. wheel directly and with precision, specifically so: that ultimately .the proper escapernentwheel tooth 28 will be caught by the escapement dog 2?.

To the end stated, there i provided a reverse rotation blocking device in the form or" a rotation checking pawl 76 pivotally carried by a screw T onthe undersideof the escapernent bracket 25. The pawl it occupies normally the positionrseen in Figures 2 and 5, fully clearof the orbitof the teeth 28 of the escapement wheel. Ateach institution of a tabulating run the downreaching .arm ll of the bell cranktt, through the intermediary of a connection comprisingan interponent rod l8, imparts a forward swinging motion to alever 89 reaching in the showings. of Figures 3- to 5, inclusive; leftwardly. from. a pivot point 3 l .on the bracket 25. Toward the end of the forward swinging .motion of thelever 80 a pin 82 engages a rear face on a lever 84. to swing the latter to the .positionseen in Figure 3,..the motion of the lever 30 being limited by an ear 39 engaging a portion'of. the br-acketiit. The lever 8% is pivotally carried by a studiiii on the underside of the bracket 25and has an arm 86 which by means of a-spring 8'! igyieIding-Iy connected with-the reverse-rotation check pawl it. Therefore, when the lever 84 is in the operated position as seen in Figure 3, thespring 8i urgesthe pawl it into reverse-rotation checking relation with the escapement wheel '28. During the movement of the levers 80 and 84 to their operated positions seen in Figure 3, a latch element 38 pivotally carried at on the lever 86', facilitatedby a spring 9| glides overanear 92.0n -the. lever 84 to..arr-ive finally in the position seen in Figure 8. Thus during tabulations and while the tabulator reed 31 remains projected, the lever 88 remains operated and therefore the check pawl 18 remains activated. Meanwhile, a nose on the latch element 88 rests under the tension of the spring 9| against a pin 98. The escapement wheel during the tabulation turns in the direction of the arrow indicated in Figure 3 and the escapement wheel teeth 28 advance and glide idly over a back face 95 on the check pawl 18. As the tabulator stop ll meets the counterstop, one of the escapement wheel teeth 28 will have passed slightly beyond the check pawl 18 and the latter will springmove into rebound checking position behind such tooth. When the tabulator stop [1 clashes against the counterstop reed 31, as before stated, the latter restores responsively under the power of the spring 6 I and substantially ooncomittantly the carriage l i rebounds. The escapement wheel 28 rebounds also, but del-ayedly due to the stated capacity for out-of-step movement. The rebound check pawl it meanwhile stands ready in position behind the appropriate escapement wheel tooth 28 to stop reverse rotation of the escapement wheel 28 as shown in Figure 4, said check pawl it being backed up by a motion limiting pin 95. During an initial portion of the return movement of the counterstop reed 31, the escapement wheel dog 27 moves to the escapement wheel controlling position seen in Figure 4. In such movement the escapement wheel dog 20 arrives in the position seen in Figure 4 before the reed 3'? moves out of engagement with the tabulator stop il. Meanwhile, as seen in Figure 4, the back check pawl 78 is held active by the latch 88 in cooperation with the car 92, even though the pin 82 leaves the before stated face on the lever 84. After the parts assume the position seen in Figure 4 the reed 31 continues its retracting movement and the lever arm ll leaves the escapement dog as in Figure 5. During the very last increment of retracting movement of the reed 3'! the pawl 88 rides ofi the edge of the ear 92, wherefore the reverse-rotation check pawl 16 stays active sufiiciently late beyond the instant of rebounding action of the carriage transmitted to the escapement wheel. As the lever 88 nears the fully normal position seen in Figure 5, the latch 88 rides clear of the ear 92 and the spring 9| returns the lever 84 to the normal position seen in Figures 2 and 5, wherein the lever 84 abuts a collar on the pawl l6 and wherein the pawl is forced to idle position by the end of the arm 86 engaging the pawl it. Meanwhile the carriage l I under the power of the spring motor 18 settles in advance direction in the exact desired letter feed position, inasmuch as the escapement dog 21 will intercept the proper one of the wheel teeth 28.

Additionally to the rod 18, the connection between the arm H and the lever 80 comprises extending therebetween a pring 91 having the said rod 18 accommodated in the turns thereof. The spring 9? is very strong and always confines rod i8 snugly between the arm II and an adjustable screw [83 on the lever 88. The effect is that the rod iii, the spring 9? and the screw llil] constitute together an adjustable connection between the arm I! and the lever 88, it being understood that the screw I68 is so adjusted that the latch 88 will move clear of the car 82 at the last possible moment of the restoring movement of the arm 1 I, thereby 'to' keep the check pawl 16 sufliciently long capacitated to perform its intended function. The end of the lever 80 which carries the pawl as is guided horizontally in that the portion which carries the pawl 88 underlies the bracket 25 and in that the lever has a tongue 98 overlying the bracket 25.

Due to the stated opportunity for out-of-step movement of the escapement wheel 28 with reference to the carriage, only part of the rebound motion of the latter is transmitted to the escapement wheel, wherefore the back check pawl 16 is contacted at a later time and less violently as would be the case otherwise. Actually, due to the stated capacity for out-of-step movement, the carriage is allowed to rebound in excess of a letter feed space, while the escapement wheel 20 in its reverse rotation is restricted to somewhat less than a tooth space. In fine pitch machines this difference of rebound motion of the carriage with respect to the escapement wheel is very pronounced, and has been the source of great difi'lculty in providing for accurate, efiicient carriage control at terminations of tabulating runs. The structure of the invention on the other hand provides for simple, reliable carriage control even if the letter feed pitch of the machine is small. It is understood that at the end of each tabulation the escapement dog 2'! in conjunction with the back check pawl 76 is in perfect control over the escapement wheel 28 to cause the carriage to settle with the escapement dog 21 interceptin the appropriate tooth 28 of the escapement wheel.

Having explained the nature and object of the invention and having specifically described a preferred embodiment thereof, what is claimed is:

1. In a machine of the class described, having a carriage urged in letter feed direction and an escapement wheel operatively connected with the carriage for advance and reverse movements by the latter, the combination with an escapement means cooperative normally with said escapement wheel for letter feed control, and tabulating means for the carriage comprising tabulating control means, normally inoperatively conditioned tabulating stop means, and means responsive to said control means to operatively condition said tabulating stop means'and release said escapement wheel from control of said escapement means, and responsive to tabulating arrest of the carriage by said stop means to restore first said escapement wheel to the control of said escapement means and then to condition inoperatively said tabulating stop means, of normally incapacitated reverse-rotation checking means for said escapement wheel, and means to render said reverse-rotation checking means capacitated incident to the response of said responsive means to said control means, and to render it automatically incapacitated under control of the responsive means after said tabulat-- ing stop means becomes inoperatively conditioned.

2. In a machine of the class described, having:

-a carriage urged in letter feed direction and an.

escapement wheel operatively connected with the carriage for advance and reverse movements by the latter, the combination with an escapement cooperative normally with said escapement wheel. for letter feed control, and tabulating means for the carriage comprising tabulating control. means, normally inoperatively conditioned tabu-- lating stop means, and means operated responsive to operation of said control means to operatively condition said tabulating stop means and thereafter to release said escapement wheel. from control of said escapement, and restored rssli oi si a a ss eppi i he carriage y a step m ans, ts o efiistsad jesca em n Whe to: the control oijsaid escapement', and then to inoperatively condition the said stop means, of a reverse-rotation checking means i'or said escap'ement wheel, normally heldjincapacitated by s 'd responsively operatedjand restored means; and me to sara it s and to in a a tate said checking me ns by said responsive means respectively at operation thereof rand pending a completion offitsrestoring movement beyond a'p'osition to inoperatively 'QOIlClllllQl aid stopmeans. 3.- The combination witha machine having a frame and a carriage, and havingmeans including an escapement wheel rotatable in anad- Vance direction and a i-everse directionrespectively by movement oi'the carriage in an advance direction and by movement of the carriage in a reverse direction, of means urging normally said carriage and said rotatable means in their ad- Vance directions, escapement meansin control of said'escapement wheel and operable to permit stepwise advance rotation thereof, said 'escaperiient means including a dog normally in position for-holding theescapement wheel against advance rotation, a tabula tor stop on the carriage, a countcr stop on the frame normally but of cooperative range of said tabulator stop, a normally incapacitated device for blocking reverse rotationof saidrotatable means, means to move said counterstop into cooperative range with said tabulator stop and additionally to release said dogand render saidbl-ockingdevice capacitated, and means automatically-operated responsive to the engagement of said tabulator stop with the counterstop to move said dog to its ehective positicn,.-and also to withdraw said counterstop and thereafter to incapacitate said blockingdevice.

1-. In a machine of the class described having a frame, a carriage, means including an escapement. wheel rotatable in an advance direction and in a reverse direction respectively by movement of the carriage in advance and in'reverse directions, meansurging normally said carriage and said ,wlieel in their advance directions, and escapement means normally in control of said escapementwhcel, operable to permit stepwise advance rotation thereof'and including a normally eliectiv'e dog holding the,'escapementwheel against advancerotation only; the combination with tabulating means having.controlldevices, effective at the outset of anytabulation to place said holding dog free of said wheel and effective at each conclusion, of a tabulation to render said holding dog. again cooperative with said wheel, of means to control the escapement-wheel at each conclusion of a tabulation while the carriage rebounds, comprising a normally'retracted pawl forchecking, reverse rotation of said rotatable means, and means enabling said control devices to place said pawl under bias to move to areverse-rotation checking position at theoutset of any tabulation and to retract'such pawl short time interval after the holding dog has returned into cooperative relation with said wheel. 5. In amachine of the class described, having a carriage urged inletter feed direction and an escapement-wheel operatively connected with thecarriage-fon advance and reverse movements by ,the latter, the combination with an escape-- ment means cooperative normally with said escapement, wheel for letter feed control','-: and

tabulating means for the carriage comprising tabulating control means, normally inoperatively conditioned tabulating stop means, and means responsive to said control means topperatively condition said tabulating stop means and release said escapement wheel from control of said escapement means, and responsive to; tabulating arrest of the carriage by said step means to restore first said escapement wheel to the control of said escapement means and then to condition inoperatively said tabulating stop means, of1a reverse-rotation checking pawl for said esc apemerit wheel normally clear thereof andfl'nieans to urge said Checking pawl into cooperative-relation with the teeth of, the escapement wheel incident to the response of said' respons ive means to said control means, and means to keep said urging means active until an instant after said tabulating stop means becomes inoperativ'ely conditioned.

- 6. In a machine of the class described, having a carriage urged in letter feed direction-and an escapement wheel operatively connected with the carriage for reverse movements by the latter, the combination with an escapement cooperative normally with said escapement wheel for letter feed control, and tabulating means for the carriage comprising carriage intercepting means, and means responsive to functioning of said intercepting means to place-the esjcapement wheel under control of said escapement, of normally incapacited means for checking reverse rotation of said escapement wheel incidentto rebounding of the carriage at interception thereof,-including spring-restored means automatically operated tocapacitate said reverse-rotation checking means, means to latch said spring-restored means automatically in operatedpo'sition, and means to'release said latch means automatically a short time interval after the esca'pernent wheel is restored to the control of said escapement. 7. In a machine of the class described,having a carriage urged in letter; feed direction and an escapement wheel operatively connected with the carriage for reverse movements by the latter,

' the combination with an escape ment cooperative normally with said escapement wheel for letter feed control, and tabulating means forthe carriage comprising carriage intercepting means, and means responsive to functioning of said intercepting means to place the escapement wheel under control of said escapement; ofnormally incapacitated means" for checking reverse rotation of said escapement wheel incident to rebounding of the carriage at interception there- 1 of, including a reverse-rotation checking-means normally clear of the teeth of the'escapement wheel, means movable to an operated-position to spring-urge said checking means for reverserotation checking action on the teeth- 01 the escapement wheel, means to latch saidmovable means in operated position,andmeanscontrolled by said responsive means torelease said latch means automatically a short timednterval afterit hasplaced the escapement wheel under the control of the escapement.

HARRY C; YAEGER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,287,706 Lasker D ec. 17,1913 2,558,413 Becker ,Juneflfi, 

